There is increasing evidence that many xenobiotic chemicals (called as endocrine disruptor chemicals, EDCs) through interfering with the endocrine system, have the capability to induce developmental and reproductive abnormalities in humans and animals. The yolk protein precursor vitellogenin (Vtg) has proved to be a simple and sensitive biomarker for assessing exposure of fish to EDCs, especially the estrogenic compounds. Work is ongoing to develop screening and testing programmes for endocrine disrupting effects of new chemicals, and in the focus of this development are the fish test species common carp (
Cyprinus carpio
). In this study, we have developed quantitative enzyme-linked immunosorbent assays (ELISA) for VTS in common carp. The working range of the ELISA was 11.25 - 2000 ng/ml (75 - 25% specific binding/maximum antibody binding [B/B0]) with a 50% B/B0 intra and interassay variation of 3.9% (
n = 10) and 12.5% (
n = 30), respectively. This ELISA is capable of detecting Vtg as low as 6 ng/ml, and can accurately detect Vtg in even 10 ml of plasma. The ELISA was applied to measurement of Vtg production by male carp (
C. carpio , Cyprinidae) fish exposure to ethynylestradiol. The results showed that the amount of Vtg produced in plasma of exposed fish increased in logarithmic order comparing to the control group and the ELISA described here could be used as an indicator of water pollution to estrogenic pollutants.